In order to provide adequate heating and cooling to occupants of a passenger compartment, modern automotive vehicles typically utilize an air duct system disposed above a headliner. The headliner is attached to the inner surface of the automotive vehicle roof to conceal the air duct system so as to provide an aesthetically pleasing appearance to the passenger compartment. Outlet registers are mounted in vent openings formed at various locations in the headliner to provide air flow to specific areas of the passenger compartment.
A previously known air duct system utilizes a number of air ducts which are attached to an inner surface of the automotive vehicle roof. The air ducts include a number of outlets which correspond to the vents located on the headliner. During assembly of the automotive vehicle, an assembly team member will install the blow molded air duct assembly to the inner surface of the automotive vehicle roof. Next the openings in the headliner are aligned with the outlets of the air duct system and then the headliner is attached to the roof of the automotive vehicle.
One drawback of attaching the air duct system to the roof is that each of the outlets must be precisely aligned with the vent openings formed in the headliner prior to attachment of the headliner. As such, installation of the air duct system and the headliner results in a decrease in production efficiency due to the required installation time. However, the air duct system is advantageous in that the positions of the various other components concealed by the headliner, illustratively including wiring harnesses and transport tubing, are unaffected by the air duct system, as it is spaced above the headliner.
Another previously known air duct system utilizes preinstalled air ducts attached to the headliner. The air ducts have a generally U-shaped cross section and are fixedly secured to the headliner assembly so as to define an air flow passage. The air duct system includes an inlet for receiving directed air from the HVAC system, and covers the openings formed in the headliner. Attaching the air ducts to the headliner provides a number of advantages such as an increase in production efficiency as the air ducts are preinstalled on the headliner prior to the attachment of the headliner to the roof of the automotive vehicle. Further, the air ducts provide additional structural rigidity to the headliner.
A drawback to the above described air duct system is that a continuous seal between the air duct and the headliner is required. If the seal is interrupted, air will leak from the air duct into the space between the headliner and the roof. The loss of air will decrease the air flowing into the passenger compartment, thereby, decreasing the efficiency of the overall HVAC system.
A particular problem involves the placement of fluid transport components, illustratively including wiper fluid hoses and water drain off hoses, between the headliner and the roof. The fluid transport components often have to cross an area of the headliner covered by the air duct. The wiper fluid hoses transport wiper fluid to a rear windshield wiper dispenser, while the water drain off hoses are used to drain off water entering the slide tracks of sunroofs which can be partially surrounded by the air ducts, particularly in headliners having sunroofs disposed towards the rear of the vehicle or those having secondary sunroofs.
As the fluid transport components contains a liquid, extending the transport components above and around the air duct requires that the fluid flow uphill. Further, it is unadvisable to extend the transport components between the air duct and the headliner due to the possibility of degrading the seal. In addition, if the transport components were to rupture within the air duct fluids would leak into the passenger compartment through the vent openings formed in headliner.
Thus, there exists a need for an improved air duct system which combines the advantages of the air duct system attached to the roof and the air duct system attached to the headliner.